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First test of rival to Einstein’s gravity kills off dark matter

newscientist.com

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Re: First test of rival to Einstein’s gravity kills off dark matter

#51

Post by acqq »

beambot wrote: post #17

> String theorist Lubos Motl savaged Verlinde’s ideas in a recent blog post: “I wouldn’t okay this wrong piece of work as an undergraduate term paper.” I find this rudeness and pedantry in academia infuriating. There's no justification for this level of nastiness -- not in private, public, peer review, or science as a whole. Seeking out the unknown and creative explanations thereof is the hallmark of good science; ch…

For me, more interesting "gossip-like" detail that Motl enviously mentions is the "money" Verlinde received. Wikipedia has the details:

https://en.wikipedia.org/wiki/Erik_Verlinde

"In June 2011, the Netherlands Organisation for Scientific Research (NWO) awarded Verlinde the Spinoza Prize, the highest award available to Dutch scientists including a 2.5 million euro grant for future research.[14] The committee cited his work on the Verlinde formula, the Witten–Dijkgraaf–Verlinde–Verlinde equations, the Cardy-Verlinde formula and entropic gravity as the major achievements leading to the award."

By the way, my impression is that reading Motl is not a pleasant experience for anybody but himself.

Re: First test of rival to Einstein’s gravity kills off dark matter

#52

Post by thejollysin »

Physicist here. Please do not put too much stock in this paper.

Some of the folks on this paper are good scientists, but this appears to be more about looking for funding than good science.

Their paper on the Arxiv is about building some math to make gravity look like dark matter. But this has been done 1000 times before with no success. They have no physical basis for their math; there is no reality behind it. I do not expect this to get them the Nobel Prize.

Re: First test of rival to Einstein’s gravity kills off dark matter

#53

Post by thejollysin »

brilliantcode wrote: post #47

Can someone explain in layman's terms what really is dark matter and why there's so much obsession around it? If we can't observe it and we are only relying on inferences to explain it's effects, that seems like pretty weak set of legs. Obviously I'm missing the academic discipline to appreciate this topic but nevertheless, I'm curious about our understanding of the very fabric and mechanisms of our reality and the u…

"Dark Matter" is a phrase we use to describe a hole in our understanding of the universe. To put it simply, when we look out into space, at very large scales like galaxies, everything is just too heavy. It appears as if there is a LOT more matter out there than we can see. Things are orbiting faster than they should be, like galaxies are heavier than makes good sense..

Maybe there is some matter out there that is "dark", so we just can't see it. That would be a solution. Or maybe the laws of gravity we wrote down are bad at large scales. No one knows. Trust no one who tells you they know the answer: if they did they would have a Nobel Prize.

Re: First test of rival to Einstein’s gravity kills off dark matter

#54

Post by thejollysin »

FeatureRush wrote: post #12

What would be the next test? Clusters or that dark matter dwarf galaxy causing ripples in our Milky Way?

The "next test" would be to look at more galaxies. They did not actually try to apply their theory too many real world observations. The goal of this paper is to get funding to try and apply their new theory to a huge number of galactic measurements. Until they do THAT, no one in the physics community is going to listen to them.

Re: First test of rival to Einstein’s gravity kills off dark matter

#55

Post by shakna »

bsder wrote: post #24
beambot wrote: post #17

> String theorist Lubos Motl savaged Verlinde’s ideas in a recent blog post: “I wouldn’t okay this wrong piece of work as an undergraduate term paper.” I find this rudeness and pedantry in academia infuriating. There's no justification for this level of nastiness -- not in private, public, peer review, or science as a whole. Seeking out the unknown and creative explanations thereof is the hallmark of good science; ch…

> I find this rudeness and pedantry in academia infuriating. So you'd rather people quietly knife you in review? Because that's what happens if you penalize people for public rudeness. Personally, I'd rather have a loud critique to my face than a polite one behind my back or, even worse, no engagement at all. I don't need your politeness or friendship when I'm putting forth some new theory. I need accurate, engaged c…

There's the constructive rude:

> Mauro, SHUT THE FUCK UP! ...To make matters worse, commit f0ed2ce840b3 is clearly total and utter CRAP even if it didn't break applications. ENOENT is not a valid error return from an ioctl. Never has been, never will be. ENOENT means "No such file and directory", and is for path operations. ioctl's are done on files that have already been opened, there's no way in hell that ENOENT would ever be valid.

https://lkml.org/lkml/2012/12/23/75

And then there's this:

> It's a Category 5 loon. Popular sources are full of anti-Copenhagen crackpot pseudoscience and of exactly this kind of bullshit – claims that the proper Copenhagen quantum mechanics implies superluminal or acausal effects (for the latter, see some largely confused fresh text by Nude Socialist about entangled photons in graves, London, and Beijing: this sort of stuff gets produced every minute, it seems) – but you may still find people who think that the presentation should be even more anti-Copenhagen.

http://motls.blogspot.com.au/2012/10/evading-quantum-mechani...

Re: First test of rival to Einstein’s gravity kills off dark matter

#56

Post by quanticle »

Frondo wrote: post #42
bsder wrote: post #24

Earlier quoted context omitted.

> I find this rudeness and pedantry in academia infuriating. So you'd rather people quietly knife you in review? Because that's what happens if you penalize people for public rudeness. Personally, I'd rather have a loud critique to my face than a polite one behind my back or, even worse, no engagement at all. I don't need your politeness or friendship when I'm putting forth some new theory. I need accurate, engaged c…

Accurate, engaged criticism is great, that stuff belongs everywhere. "I wouldn’t okay this wrong piece of work as an undergraduate term paper" is not accurate, engaged criticism, it's mean-spiritedness under a veneer of toughness. It's easy and fun to be rude and insulting, and when you can get away with it because of the subculture you're writing within, why not, right? Because being a dick is being a dick no matter…

Every industry, every field, everywhere, will be better off once people get past being dicks just for fun, and give accurate, engaged criticism while maintaining civility.

I disagree. The blunt people (who come off as "dicks" to the outsiders) are like a community's immune system. They protect the community against the sort of people who take accurate engaged criticism, make one or two changes to fix specific issues, and then resubmit their work, wasting the community's time and resources, driving off the people who are making good-faith efforts to help the community. They're not being dicks "just for fun". They're protecting the time and attention of other community members by saying bluntly what many other people are often thinking.

Communities that have too many of these people become closed and ossified. Communities that have none of these people evaporate, as the core contributors just walk away and find better things to do than deal with people who are more interested in getting fame and attention for themselves than making good-faith efforts to advance the project of the community. The trick is to find a good balance.

Re: First test of rival to Einstein’s gravity kills off dark matter

#57

Post by tombone12 »

DennisP wrote: post #29
jessriedel wrote: post #19

Folks, the observation doesn't test Verlinde's idea, this tests a very general class of models, such as the well-known MOND scheme. > Milgrom, however, supports the work. He also points out that according to his own 2013 analysis of gravitational lensing data in galaxies, MOND produces similarly impressive results as Verlinde’s gravitational model does in Brouwer’s study. (Also: http://motls.blogspot.ca/2016/11/verli…

Seems like it's pretty easy to make dark matter a good fit, because you can just adjust the presumed distribution of dark matter to fit the data.

people who just make up dark matter distributions are morons, obviously you use a model derived from the theory.

Re: First test of rival to Einstein’s gravity kills off dark matter

#58

Post by DennisP »

jessriedel wrote: post #35
DennisP wrote: post #29

Earlier quoted context omitted.

Seems like it's pretty easy to make dark matter a good fit, because you can just adjust the presumed distribution of dark matter to fit the data.

Nope, this is only an issue on galactic scales and below. On supergalactic scales, where most of our data comes from, the DM distribution is determined by theory. That includes all the stuff I mentioned: LSS, CMB, bullet cluster, etc.

So, my impression from popular articles is that physicists don't actually know what dark matter is, and have a fair number of candidate ideas. According to the theory that makes good predictions, what is dark matter made of?

Re: First test of rival to Einstein’s gravity kills off dark matter

#59

Post by sn9 »

beambot wrote: post #17

> String theorist Lubos Motl savaged Verlinde’s ideas in a recent blog post: “I wouldn’t okay this wrong piece of work as an undergraduate term paper.” I find this rudeness and pedantry in academia infuriating. There's no justification for this level of nastiness -- not in private, public, peer review, or science as a whole. Seeking out the unknown and creative explanations thereof is the hallmark of good science; ch…

That's pretty much what academia told Motl.

He hasn't been a working physicist for a long time precisely because of how unnecessarily and uncharacteristically nasty he is.

Characterizing him as an example of any sort of trend in academia is both uninformed and deeply insulting.

Re: First test of rival to Einstein’s gravity kills off dark matter

#60

Post by Avshalom »

brilliantcode wrote: post #47

Can someone explain in layman's terms what really is dark matter and why there's so much obsession around it? If we can't observe it and we are only relying on inferences to explain it's effects, that seems like pretty weak set of legs. Obviously I'm missing the academic discipline to appreciate this topic but nevertheless, I'm curious about our understanding of the very fabric and mechanisms of our reality and the u…

So basically there are four forces: weak and strong nuclear forces; gravity and EM.

EM is mediated by photons and visible matter is constantly absorbing and emitting photons.

Some particles don't though. Neutrinos for instance. They're dark, they don't interact with light.

So when observation showed that there needs to be more matter laying around than we could see some enterprising young turks said "hey, maybe there's a shit ton of dark matter" and that makes the math come out right.

the obsession is mostly because people who aren't astronomers seem to think "dark" is a metaphor and go "aha now that no one cares about the oxford comma this will be my new opinion"

Up for debate is what kind of particles make up the dark matter and how much mass is dark vs just poor measurements and/or some tweaks to gravity, but unless some one manages to disprove neutrinos: dark matter exists.

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